The study will test (1) if OSAS causes secretion of ACTH, cortisol, growth hormone, prolactin, beta-endorphin and catecholamines, (2) if treatment of OSAS with nasal continuous positive airway pressure abolishes the neuroendocrine response, and (3) if the post-apneic ventilatory response and the response to flow resistive loading can be acutely restored to normal by naloxone.